Coextrusion of two or more different polymers or polymer compositions enables forming composite sheet or film products that have components defined by distinct layers or zones corresponding to each material extruded. Depending on how the compositions are extruded, each material may be laminated one on top of another across the film and/or be disposed across the film side-by-side to one another. Some coextrusion techniques include independent temperature control associated with the different polymers in order to accommodate layers having thermally distinct processing requirements or equalize layer thickness when each material is laminated one on top of another across the film. Another issue that arises in particular with respect to side-by-side interfacing of the polymers in the film involves mechanical stability where the different polymers connect. When the different polymers are side-by-side, edge seams provide relatively less surface area to establish lamination than if the polymers are laminated one on top of another across the film.
The films in which the different polymers are edge laminated require selection of the different polymers to ensure compatibility during processing. If the different polymers lack compatibility, the components separate upon extrusion and fail to form a unified film inclusive of each region of the different polymers across the film. This requirement places an undesirable limitation on what polymers may be chosen. Compatibility needs thus dictate the different polymers that can be effectively used, thereby limiting or preventing selection of the different polymers based on other criteria such as costs, physical characteristics or other properties of actual commercial interest.
Therefore, there exists a need for improved cross directional zoned multiple component films, laminates utilizing the films, and systems and methods of coextruding the films.